A solid-lubrication rolling bearing using a solid lubricant is suitable for use at elevated temperatures or in a vacuum, which prevents use of grease or lubricating oil as a lubricant, for example, for use as a tenter clip bearing of a film stretching machine.
The film stretching machine herein is a machine for manufacturing a stretched film used in general packaging materials, liquid crystal panels, or secondary batteries. To improve the strength of the film, as illustrated in FIG. 25, the film stretching machine continuously transfers a film 100 in a longitudinal direction (direction of an arrow X), and stretches the film 100 in its width direction in a region expressed by a broken line while heating the film 100 (potentially, further stretches the film 100 in its longitudinal direction). The tenter clip is a mechanical component in the film stretching machine, which clips both ends of the film, and stably circulates along a caterpillar guide rail as illustrated by an arrow C in this figure to stretch the film in a predetermined direction. The tenter clip bearing is used in a portion that guides travelling of the tenter clip along the rail at elevated temperatures (250° C. or higher, and about 400° C. at maximum). Therefore, it is necessary to use the solid-lubrication rolling bearing.
Patent literature 1 discloses, as the solid lubricant used in the solid-lubrication rolling bearing, a solid lubricant that is a sintered compact including graphite and a binder, the sintered compact having a combination ratio of graphite of 80 to 98 vol %, a bending strength of 4 to 15 MPa, and a specific wear rate of 1.5 to 2.5×10−5 mm3/(N·m).